Abrasive wheel



May 12, 1959 C. F. WHITAKER ABRASIVE WHEEL Filed Jan 51, 195

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INVENTOR CARL F. WHITAKER BY KENWAY, mun. wrrrm & mumrm ATTORNEYS United States Patent ABRASIVE WHEEL Carl F. Whitaker, Beverly, Mass. Application January 31, 1957, Serial No. 637,554 4 Claims. (Cl. 51-194) In finishing operations wherein the surface of an article is abraded, scoured, ground, sanded, bufied or burnished, it is the conventional practice to secure to the periphery of an abrading wheel or cylinder a strip of material carrying an abrading substance of the desired degree of hardness and fineness. For example, rough finishing may require a 40 to 60 grit paper or cloth, as compared to an 80 to 100 paper or cloth for fine finishing. Such papers and cloths vary in weight, thickness and flexibility, and it is recognized that an abrading wheel which may satisfactorily handle one type or weight of paper will not necessarily handle a heavier or lighter paper and still be concentric and smooth running.

Abrading wheels usually operate at relatively high speeds and it is therefore necessary that their design be such as to insure static and dynamic balance, and provision must be made to permit a quick replacement of paper without affecting the static and dynamic balance.

The principal objects of the present invention are to provide an abrading wheel which will handle all commercially available abrasive papers and cloths without danger of severing their end portions when being secured to the wheel or cylinder, and to provide an abrading wheel which is of durable construction, which is eflicient and reliable in operation and which meets the various requirements of industrial usage.

Further objects relate to features of construction and will be apparent from a consideration of the following description and accompanying drawings, wherein:

Fig. l is a side elevation of an abrading wheel constructed in accordance with the present invention;

Fig. 2 is an end elevation, with parts in section, of the abrading wheel shown in Fig. 1;

Fig. 3 is a section through the abrading wheel showing the clamping screw and associated parts;

Fig. 4 is an end view of the clamping screw;

Fig. 5 is a side elevation of the clamping screw and associated parts;

Figs. 6 and 7 are side and plan views of the combined clamping member and spacer; and

Fig. 8 is a perspective view of the clamping member and spacer shown in Figs. 6 and 7.

The numeral 1 designates the body of an abrasive wheel which may be cast or cut from suitable stock, such as steel, aluminum, etc. and is provided with a central bore 2 and a radial slot 5 which flares inwardly as shown in Fig. l, and terminates in a transversely extending opening or bore 6 (Figs. 2 and 3) which receives a split locking screw 8. At a diametrically opposite position on the body of the wheel from the opening 6 there is provided an opening which receives a counterbalancing stud 10 so that the wheel can be operated at high speed without chattering or objectionable vibration.

The periphery of the wheel is preferably provided with a rubber or felt facing 12 which may be of any desired thickness, and either one or both faces may be flanged, as illustrated in my copending application, Serial N0.

2,885,835 Patented May 12, 1959 541,153, filed October 18, 1955. The particular wheel here shown is designed to be clamped to the shoulder end of a drive shaft and it is to be understood that the wheel may be provided with any conventional type of holding means.

The clamping screw 8 comprises a head or cap 14 provided with four circumferentially spaced recesses 15 for the reception of the jaws of a spanner wrench, and integral with the head 14 is a split or slotted locking shank 16, the free end of which is provided with threads 18. The adjacent longitudinal edges of the split shank 16 along one side are rounded, as shown in Fig. 4, and may be designated by the letter R, while those along the opposite sides are relatively sharp, as indicated by the letter S, both letters being applied as indicia to the head of screw 8 to guide the user. When using a strip 20 of relatively coarse paper or cloth, say up to number 60, the ends are inserted so that they pass over one of the rounded edges R, thus avoiding cutting or breaking which is otherwise apt to take place. When using a relatively fine paper or cloth, e.g., number or higher, it is inserted so that the sharp edges S bite into the paper or cloth to hold it against slippage. Thus, for coarse paper or cloth the rounded edges are necessary to hold it without breaking, but for fine paper or cloth the sharp edges are effective to produce the necessary bite.

In order to provide a reliable clamping surface and also to maintain the two parts of the split shank 16 from being cammed-in by the locknut 21 and thus ultimately stripping the threads from the locking screw 16, I provide an annular member or key washer 22 which fits about the shank 16 so as to seat against one face of the wheel 1. Carried by this member is an outwardly projecting tongue or key 24 which fits between the outer ends of the split shank 16 to hold the two sections from being forced inwardly when the nut 21 is applied and tightened.

A particularly advantageous feature of this construction is the speed and the ease with which a fresh strip of abrasive may be applied, it being noted that it is merely necessary to remove the locking nut 21, key washer 22, screw 16, and used strip 20, and then pass the free ends of the fresh strip into the slot and reapply the screw 16, key washer 22 and locking nut 21, after which the screw may be turned so as to draw the fresh strip about the periphery of the wheel with the desired degree of tension and then tighten the nut 21. If desired the abrasive strip 20 may be tightened to any tension on the wheel, or loosely applied so that it is in out-of-contact relation to the outer periphery except at those points at which it enters the slot 5. With a loosely applied abrasive strip on the wheel there is, in effect, an air cushion between the strip and the periphery which is highly advantageous in that it not only permits a more gentle abrasive action than would otherwise be possible, but also it is effective to eliminate the burr-like formations at the edges of the peripheral surface due to the transverse flexing of the strip.

While I have shown and described one desirable embodiment of the invention it is to be understood that this disclosure is for the purpose of illustration and that various changes and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. An abrasive wheel comprising a rotary member having a cylindrical surface and a radial slot extending inwardly from said surface and terminating in a transversely extending opening having an axis parallel to the axis of said rotary member, a screw having a split shank extending through said opening, said split shank receiving the opposite end portions of an abrasive strip extending about said surface and inwardly through said slot so as to anchor them, a removable spacer interposed between the free end portions of said split shank so as to maintain the efiective diameter of the threads of said screw, and a locking nut holding said screw against rotation so as to maintain a fixed tension on said strip.

2. An abrasive wheel comprising a rotary member having a cylindrical surface and a radial slot extending inwardly from said surface and terminating in a transversely extending opening having an axis parallel to the axis of said rotary member, a screw having a split shank extending through said opening, said split shank receiving the opposite end portions of an abrasive strip extending about said surface and inwardly through said slot so as to anchor them, a clamping member having an annular base extending about the threaded end portion of said screw and an inwardly extending spacer tongue interposed between the free end portions of said split shank so as to maintain the effective diameter of the threads of said screw, and a locking nut engaging said annular 4 base and holding said screw against rotation so as to maintain a fixed tension on said strip.

3. An abrasive wheel as set forth in claim 1, wherein the adjacent edges of said split shank are symmetrically rounded so that sheet material with coarse grits may be bent about the rounded edges without cracking the sheet material and the other edges of said split shank are straight so that sheet material with relatively fine grits may be bent about said other edges without cracking the sheet material.

4. An abrasive wheel as set forth in claim 1, wherein said radial slot flares inwardly.

References Cited in the file of this patent UNITED STATES PATENTS k My 

